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Beginner Joined: 23 Aug 2002 Posts: 10 Location: Canada

I'm developing a COM component which I intend to use from Zmud. Everything works fine with it, except that ZMud doesn't seem to have a facility for disposing of a COM object.

Contrived example:

MASTER Joined: 28 Nov 2000 Posts: 4817 Location: USA

I've never used COM but I believe you need to use #COM or #CALL to execute the method which closes your COM object.

Apprentice Joined: 26 Sep 2001 Posts: 124

I'm no expert at this but i believe that calling the COM object to close itself only does half the job.

Ive tested this using a system monitoring tool (TaskInfo2003 - Great Tool) and the following script.

#ALIAS RoomKind {#VARIABLE Conn %comcreate( "ADODB.Connection");temp=%concat( "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=", @LocalMapDatabase);#CALL @Conn.Open(@temp);#IF (@Conn.ConnectionString ="") {#SAY {%ansi( red)testing%ansi( white): Couldn't open connection to database.};#ABORT 1} {#ECHO open};#VARIABLE rs @Conn.Execute(%concat("SELECT k.name FROM KindTbl AS k, ObjectTbl AS o WHERE k.KindId = o.KindId AND o.ObjId =", %1,";"));#ECHO @rs.GetString;#CALL @rs.Close} "zMapperExtender"

This script simply creates an RoomKind alias, which takes as it's 1st parameter a room number, and returns the RoomKind name. Very handy to incorporate into zmud scripts.

As you can see, the alias calls the COM object to close itself with #CALL @rs.close, but this does not close the ADODB connection to the database.
Basically this means that everytime this alias is executed a new ADODB connection is created.

Does anyone know how to unload these ADODB connections once they are loaded?
(Note: I don't mean {#var Conn %null} as this simply unreferences the Connection)

Apprentice Joined: 26 Sep 2001 Posts: 124

#unvar Conn
Doesn't seem to work either.

SubAdmin Joined: 18 Nov 2001 Posts: 5182

I believe that right now zMud simply does not have the facility to properly release these objects. Zugg stated somewhere that when it is time to update zMud again he will be improving the COM support with things he has learned in writing zApp. Until then scripts that make heavy usage of COM either have to reuse the objects or you will just have to periodically close and relaunch zMud.

Adept Joined: 10 Jan 2002 Posts: 264 Location: USA

did this ever happen? i really could use a %comdestroy(), i have a perl script that i'd like to be able to edit/save then reload with the new settings. but apparenly from searching the forums i needa restart zmud each time?

Posted: Thu Jun 09, 2005 5:35 pm

Actually, if using

#VAR ComObject ""

isn't release it, then that's a bug. I'll check into this. You don't need any special functions for destroying COM objects. Windows is *supposed* to handle the memory management of COM objects for you, so just clearing the variable is supposed to be good enough. It's equivelant to saying

ComObject = nothing

in VBScript. Now, it's possible that Windows is somehow caching the object internally. But in your ADO example, calling the @rs.close does *not* release any of the COM objects. It is creating a new connection each time you run it because you are calling %comcreate. Calling %comcreate forces Windows to create a new COM object no matter what you have done before. Anyway, try adding the

#VAR Conn ""

to your script, since you definitely need that.